You can manage your tasks as well as their deadlines with an application in Office 365 subscription i.e. Microsoft To-do. As it is integrated with Outlook, all your Outlook tasks are synced with to-dos under To-Do list in Microsoft To-Do App. So watch this video to explore more about this feature in Microsoft To-do. To learn more about Microsoft To-Do, watch this video : How to track Task Deadline?   

We, at Foetron, are a team of Cloud Evangelists who sell Office 365, provide migration & deployment resources and train organizations on Office 365, Teams, Project, Visio, Yammer, Delve, Planner, Booking and Office productivity tools. We are working to empower organization to take the journey of digital transformation.